Agricultural machine



June 6, 1944- w. G. CHARLEY AGRICULTURAL MACHINE Original Filed Aug. l5, 1941 4 Sheets-Sheet 1 June 6, 1944- w. G. GHARLEY AGRICULTURAL MACHINE Original Filed Aug. l5, 1941 4 Sheets-Sheet 2 June 6, 1944. w. G. CHARLEY 2,350,583

AGRICULTURAL MACHINE original Filed Aug. 15, 1941 4 she'ts-sheet s June 6, 1944. w. G. CHARLEY AGRICULTURAL MACHINE Original Filed Aug. 15, 1941 4 Sheets-Sheet 4 Patented June d, 1944 UNITED srAras l v AGRICULT MACEENE i'irlglnal applicationdngust l5, itil, Serial No,

3l, Divided and this application January 2@ @Reima The invention relates to agricultural machines, and it is concerned more specifically with an irnproved implement adjusting mechanism adapted for use on cultivators and on machines or a similar character. The present application is a divisionoi application, Serial No. dll'il, filed on August l5,l 194i for ,Agricultural implement.

In cultivators and like machines which have a ground working implement it is usual to provide ier adjustment oi the implement so that it may he lowered into a working position and raised from the Working to a non-working position. When the implement is adjusted to its working position the draft iorce and the soil reaction to which it is subjected in operation may tend to orce the implement out o' the ground under certain conditions; for instance, in a cultivator the shovels usually have at tendency to jump out ci the ground when they run into a hard spot or into a local rise of the ground; and suitable provisions must he made for holding the implement in its working position under those conditions. if the implement is relatively heavy its weight may be sufficient to hold it in the ground, but in many instances, as in cultivators, the strength requirements are not such as to call for a relatively heavy construction which would afford suilicient weight to hold the implement in the ground. In that case the adjusting mechanism for the implement may be constructed so as to prevent or restrain the implement from being forced out of the ground under all normal and under certain abnormal conditions of operation of the machine, and it is the principal object of the invention to provide an improved implement adjusting mechanism which will accomplish that result.

More specifically, it is an object of the invention to provide an implement adjusting mechanism ofl the mentioned character which is operable in implement raising direction by a suitable actuating device; which is self-actuating in implement lowering direction; and which requires no substantial holding power by the actuating device in order to restrain or prevent the implement from being forced out of the ground by the draft force and soil reaction to which the implement is subjected in operation of the machine.

A further object of the inventon is to provide an agricultural machine having an implement adjusting mechanism and actuating device therefor as outlined above, in which the actuating device is operable between predetermined limits in one drection to raise the implement from a working to a non-working position, and in the opposite direction by gravitational movement of the implement from its non-working position, the potential energy oi the raised implement being suitably controlled to hold the implement in 'its raised position for any desired length oi time.

A further object of the invention is to provide an implement adjusting mechanism as outlined hereinbeicre and incorporating a device :tor changing the depth of soil penetration of the implement.

A stili further object ci the invention is to provide an improved depth changing device aording what is known as a constant height lift," and to incorporate such improved constant height lift device in an implement adjusting mechanism having the specific :features outlined hereinbetore.

.another object of the invention is to provide a tractor mounted implement having iront and rear tools, in which the iront and rear tools are interconnected for raising movement by a single actuating mechanism, and in which the rear tools, in their lowered position, are not liable to be raised out of the ground if one or more of the frontl tools, while adjusted to a lowered or ground engaging position, should temporarily` tend to ride to a higher level, as may occur during advance of the machine.

A further object of the invention is to provide an improved implement adjusting mechanism incorporating the features outlined hereinbeiore and which may be equipped with a balancing spring, or with a plurality of such springs, in order to facilitate its operation.

A still further object of the invention is to provide an improved implement adjusting mechanism incorporating the features outlined hereinbefore in a relatively simple and compact structure, which will be efficient in operation and which may be manufactured at relatively low costs.

With the foregoing objects in view the invention contemplates an implement adjusting mechanism incorporating a link and lever system for transmitting movement from an actuating element to an implement, and in which the link and lever system is so arranged that when the implement is in its working position the link and lever system occupies a toggle position in sumciently close proximity to a dead center position thereof to afford a relatively high initial resistance against any reactive force tending to move the implement from its working to its nonworking position, and a relatively low resistance against a positive force exerted upon the link and lever system by the actuating element and tending -to move the link and lever system out of said toggle position in a direction away from said dead center position in order to move the implement from its working to its non-working position.

The link and lever system as contemplated by the invention has a Jgiitable connection with the traveling support on which the implement is adjustably mounted, so that, when the implement is in its working position and the link and lever system is in its mentioned toggle position, at least a major part of any reactive force which tends to move the implement from its working towards its non-working podtlon will be taken up by the traveling support independently of the actuating element which may have a permanent operating connection with the link and lever system. As a result, the actuating element will not be required to exert any substantial holding power, while the implement is in its working position, in order to restrain or prevent the implement from moving from its working towards i 'non-working position, and this constitutes one the major features of the invention.

In order to raise and lower the implement, as in a cultivator, a swingable arm suitably connected with the implement and to be referred to as aliiting arm" may be mounted on. the traveling support, and the actuating element for moving the lifting arm from an implement lowered to an implement raised position may be parma-- nently connected to a rock arm which is likewise swingably mounted on the traveling sup- Drt and which forms an element of the link and lever system. 'I'he invention contemplates an movement of the implement from its raised to its lowered position, and as a result the actuating element will also be returned to its starting position by said gravitational movement of the implement. The link and lever system is moreover contemplated to be arranged in such a manner that when the lifting and rock arms. are in their implement lowered and starting positions, respectively, the link and lever system will occupy its mentioned toggle position affording a relatively high initial resistance against movement of the link and lever system under a reactive force exerted by the implement upon the lifting arm, and a relatively low resistance against movement of the link and lever system by operation of the actuating element. When the rock arm, in the mentioned arrangement of tik link and lever system, occupies its starting position a reactive force of the implement will be taken up at least to a major extent by the traveling support so that the rock arm will not be subjected to any substantial force which would tend to move it in implement raising direction, and it` will therefore not be necessary to lock the actuating element after it has been returned to its starting position by the mentioned gravitational movement of the implement. v

An implement adjusting mechanism incorporating a link and lever system as outlined above. affords several advantages from a practical standpoint. vli'or instance. if it is desired to use a hydraulically operated device to furnish the lifting power for the implement. such device may simply consist of a single acting hydraulic jack comprising a cylinder and a piston movable thereassenso in by admission of fluid pressure into the cylinder at one side of the piston, one of the relatively movable elements of the hydraulic jack, for instance the cylinder, being mounted on the traveling support, and the other being permanently connected with the rock arm. After the implement has been raised by admission of fluid pressure into the cylinder it may be held in its raised position by suitable control of the operating fluid, and when it is desired to lower the implement all that is necessary is to release the iluid pressure whereupon the implement will move under its own weight to its working position and simultaneously return the piston to its starting position within the cylinder. While the piston is in its starting position the hydraulic jack is substantially ineffective to oppose movement of the rock arm in implement raising direction, but the implement will nevertheless' be considerably restrained or prevented from coming out of the ground due to the mentioned arrangement of the link and lever system.

In the case of a machine having front and rear mounted implements, such as a tractor cultivator, the front tools may be connected with the lifting arm, and the rear tools may be connected with the rock arm. so that the front and rear tools will'be raised by movement of the rock arm in implement raising direction. The mentioned arrangement of the link and lever Isystem will then be effective to restrain or prevent the front tools from coming out of the ground without exerting a substantial lifting force upon the rear I tools.

The foregoing and other objects and advantages of the invention will be more fully apparent from the following description of a preferred embodiment of the invention shown in the accompanying drawings. Referring to the drawings in which like reference characters designate the same or similar parts in the various views:

Fig. l is a side view of a tractor and cultivator mounted thereon, showing the cultivator adjusted to an operative position, the near rear wheel of the tractor being omitted to expose rear connections of the cultivator with the tractor;

Fig. 2 is a top view of the machine shown in Fig. l:

Fig. 3 is a. rear view of the machine shown in Fig. l;

Fig. 4 is a schematic view showing the front frame of the cultivator and associated parts at a reduced horizontal spacing from the rear part l Fig. 5 is an enlarged section on line V-V ofy Fig. 1;

Fig. 6 is an enlarged view of the adjusting mechanism for the front and rear implement units shown in Fig. 1, the rear unit being shown vin the same position as in Fig. 1, and the front unit being shown adjusted to a position of deepest `soil penetration; and

Fig. 7 is a partial view of the mechanism shown in Fig. 6, illustrating a different position ofthe mechanism to which it may be adjusted in order to decrease the depth of soil penetration of the front unit. l f

The tractor shown in the drawings is a tricycle type' tractor having widely spaced rear wheels l and 2 and a pair of closely spaced front wheels 3 and 4 centrally ahead of the rear wheels I and 2. An upwardly arched rear axle structure on which the rear ywheels are mounted comprises a central gear casing 6 and side arms 1 and 8 having outer housing portions 1' and 8' depending at the outer ends of the side arms and enclosing final drive gears for the/rear'wheels I and 2. Secured to the gear casing 6 at the forward side of the rear axle structure is a torque tube casing 9 which has an elongated relatively narrow portion extending longitudinally of the tractor and terminating at the forward end of the torque tube casing in a rearwardly tapering bell housing having mounting pads I I at opposite sides of the tractor. An internal combustion engine I2 is rigidly secured to the torque tube casing 9, at the forward end of the bell housing. and a bracket I3 secured to the forward end of the engine I2 is supportingly connected with a pedestal I4 on which the front wheels 3 and 4 are mounted. An operators seat at the rear of the tractor comprises a seat cushion I5 supported by longitudinal frame bars I1 and I8 secured intermediate their ends to the side arms ll and d of the rear axle structure and connected f together at their forward ends by a cross-bar I8 mounted on and extending transversely of the torque tube casing 9. The operators seat also includes a backrest 2| which is supported on the support for the seat cushion at a, suitable distance above the seat cushion. A steering wheel 22 within reach of an operator seated on the cushion it is operatively connected with the front wheels il and i by a steering mechanism including a reach rod 253 at the left side of the tractor.

Referring to Fig. 2, a square cross-bar 24 extends transversely of the tractor below the engine i2 and is rigidly secured to the bracket I3 by a pair of hangers 26, the hangers being detachably secured to the bracket I3 by bolts 21. The crossbar 24 serves as a forward support for a pair of draft frames 28 and 29 at opposite sides of the tractor. The draft frame 28 comprses a pair of square tubular draft bars 3l and 32 which are rigidly connected at their outer ends by a plate member 33 and at their inner ends by a strap 34 which has ya bent rearward extension bolted to the mounting pad II at the left side of the tractor at 36. Secured to the forward draft bar 28 is an angle clip 31 and a. U-clip 38, the angle clip 31 having an upper leg overlying the crossbar 24, and a bolt 39 extends through the upper leg of the clip 31 and is screwed into a tapped hole at the outer end of the cross-bar 24 to rigidly secure the clip 31 to the cross-bar 24. The U-clip 38 is open at its forward end, and its legs are spaced to provide a close t on the cross-bar 24 at the top and bottom sides of the latter.

Referring to Fig. 1, it will be noted that the draft bar 32 is arranged rearwardly of and above the draft bar 3| and that the seating surface of the cushion I6 of the operators seat is arranged below a plane, indicated at 4I, through the axes of the draft bars 3| and 32; l The draft frame 29 at the right side of the tractor is constructed and arranged in the same manner as has just been described in connection with the draft frame 28, that is, the draft frame 23 comprises a pair of square tubular draft bars 42, 43, as shown in Fig. 2, which extend transversely of the tractor and are offset relative to each other so that their axes will coincide with the plane 4I. An angle clip 31' corresponding to the angle clip 31, and a U-clip 38', corresponding tothe U-clip- 38, connect the draft frame 23 Ato the cross-bar 24 at the right side of the tractor, and a strap 34', corresponding to the strap 34, is bolted to the mounting pad II atthe right side of the tractor at 38'.

A pair of plate members 44 and 46 are secured to the draft frame 28 for adjustment transversely of the tractor, a series of holes 41 and 48 being vprovided in the draft bars 3l and 32, and the plate members 44 and 48 having holes 58 and 50 for the reception of bolts 49 and 5I. A similar pair of plate members 52 and 53 are adjustable mounted on the draft frame 28, the draft bars 42 and 43 having longitudinal series of holes 41' and 48', respectively.

A channel shaped bracket 54, see Figs. l and 5, is secured in a depending position to an oblong velevated portion 55 (Fig. 2) of the plate member 44, and a similar depending bracket is secured to each of the plate members 48, 52 and 53. The depending brackets serve to transmit draft to individual forward implement units, which are arranged in pairs at opposite sides of the tractor. The outer implement unit at the left side of the tractor comprises a rig beam 5G, an 'opstanding channel shaped bracket 51, and a cultivator shovel, or a plurality of such shovels, mounted on the rig beam as more fully explained hereinbelow. A pin 58 is journaled in bushings 83 and Sil (Fig. 5) at the lower end of the depending bracket 54, and carries a lower draft link 6I which is press fitted at its forward end upon the pin 58 between the bushings 6D, 68'; An upper draft link 52 is similarly press fitted at its forward end upon a pin 59 which is journaled in bushings similar to the bushings 60, 6D at an upper portion of the depending bracket 54. The rear end of the lower draft link 6l is press fitted upon a pin 63. and the ,rear end of the upper draft lnk B2 is press f1 ted upon a pin 64, the pins 63 and 64 being journaled on the upstanding bracket 51 of the implement unit in rear of the bracket 54. Referring to Fig. 5` the pin B3 is journalcd in bushings 65, 65' at the lower end of the upstanding bracket 51, and similar bushings are provided at the upper end of the bracket 51 to mount the pin 64. The implement unit comprising the rig beam 56' is thus mounted for up and down movement relative to the traveling support represented by the tractor.

A tool shank 66 is secured to the rig beam 55 by a clamping device 81 permitting vertical adjustment of the tool shank 66 on the rig beam 55, and a cultivating shovel 68 is mounted on the lower end of the tool shank 66 in the usual manner by an adjustable connection 59 permitting pivotal adjustment of the cultivating shovel about a pivot center 1I to vary the suction of the cultivating shovel 68. The shovel 68 is releasably held 'in its operative position on the tool shank 65 by a spring trip mechanism 12 of conventional construction.

Secured to the lower link 6I between the brackets 54 and 51 is an arm 13 which extends upwardly from the lower link and is offset towards the tractor to permit movement of the arm past the bracket 54 in a forward direction about the pivot center 58. The arm terminates at its upper .end below the draft frame 28 .at such a distance therefrom that it may clear the forward draft bar 3l when swung forwardly as shown in Fig. 4. The arm 13 constitutes a lifting arm for the implement unit comprising the rig beam 5S. and it is movable about the kpivot center at 58, which is fixed on the traveling support, from an implement lowered position as shown in Fig..1 to an implement raised position as shown in Fig. 4, and vice versa. in'a generally fore and aft direction.

Referring to Fig. 2, the rig beam 88 has a for- 2; ward portion extending longitudinally of they tractor and a rearward portion at an angle relative to the forward portion, extending rearwardly and away from the tractor, the rearward portion affording a section for mounting another cultivating shovel (not shown) in laterally offset relation to the cultivating shovel 88. Another implement unit comprising arig beam 14 is connected with the depending bracket of the plate member'48 by means of a pair of lower and upper draft links in the same manner as has been described hereinbefore in connection with the implement unit comprising the rig beam 88. The

rig beam 14 is similar to the rig beam 88, buty angled in the opposite direction so that the rear portion of thefrig beam 14 extends rearwardly towards the tractor. A cultivating shovel 18 is mounted on the forward portion of the rig beam 14 in the same manner as the cultivating shovel 88 is mounted on the rig beam 88, and the implement unit comprising the shovel 18 may be raised and lowered in the same manner as the implement unit comprising the shovel 88, that is, by means of a lifting arm 11 (Fig. 2) secured to the lower one of the draft links which are pivoted on the depending bracket of the plate member 48.

The spacing between the plate members 44, 48 on the draft frame 28 is such as to permit the shovels 88 and 18 to travel at opposite sides of a plant row extending longitudinally of the tractor, and the shovels 88 and 18 may conveniently be adjusted to work closer to orfarther away from such plant row -by the described adjustment of the plate members 44, 48 on the draft frame 28.

Another pair of rig beams 18, 18 corresponding to the rig beams lilil and 14 are arranged at the other side of the tractor and connected with the depending brackets of the plate members 82 and 88, respectively, in the same manner as has been ldescribed hereinbefore in connection with the mounting of the rig beams 88 'and 14 on the draft frame 28. That is, the rig beams 18, 18 may be raised and lowered by fore and aft movement of lifting arms 8|, 82 about lower pivot centers on the brackets depending from the plate members 82 and 58.

Referring to the rear part of the cultivator, which is mounted at the rear of the tractor, a stationary bracket 88 ls secured to the left frame bar I1 by a pair of bolts 84, the bracket having a bearing boss 88 (Fig, 3) and extending upwardly beyond the bearing boss 88 to provide a pivot center at .81. Another stationary bracket 88, correspondingto the bracket 88, is secured to the outer end at the left side of the tractor and a rock` arm 84 at the rightV side of the tractor.

Pivoted on the outer end of the rock arm 88 at 88 (Fig. 1) is a bent strap 81 and a link 88 extends between the lower end of the strap 81 and a bracket 88 on the tractor. The rock arm- 88 and the link 88 cooperate vto guide 'the strap 81 for up and down movement relative to the tractor.

The rock arm 84 at the right end of the cross y assasse shaft n extends in4 the same direction as the rock arm 88, and another strap |.8I (Fig. E), corresponding to the strapy 81, is pivoted on the A rock arm 84 at |82 and connected at its lower end with a bracket |88 on the tractor by a link |84 (Fig. 2) corresponding to thelink 88. The straps A 81 and'I8I carry a transverse beam |88 which has a pair of gussetplates |81 welded thereto adjacent to the straps 81 and |8|, the gusset plates being rigidly secured, respectively. to the straps 81 and I8I The transverse beam |88 carries a pair of trackeradicating tools, |88, |88 behind the rear wheels I and 2, respectively, of the tractor, and a third track eradicating tool in position to loosen the soil on the track of the front wheels 8 and 4 of the tractor. The beam |88 and the track eradicating tools |88, |88 and III constitute a rear implement unit which is connected with the rock arms 88 and 484 for up and down movement relative to the tractor, and the rock arms are swingable in a generally up and down direction from an implement lowered position, as shown in Fig. 1, to an implement raised position, as shown in Fig. 4, and vice versa, about the axis of the cross shaft 82, that is, about xed pivot centers or about a fixed pivot axis on the tractor.

Aone-way actuating mechanism for moving the rock arms 88 and 84 from theirv implement lowered to their implement raised position comprises a hydraulic cylinder ||2 which is pivoted on a pin I I8 (Fig. 2) welded to the lower flange of the frame bar I8. A piston or plunger |I4 cooperating with the hydraulic cylinder 2 is pivotally connected at II8 to a pair of arms |I1 on the rock shaft 82. Secured to one of the arms |I1, see Fig. 1, is a bracket |18 on which a crank screw |14 is adjustably mounted, and the right frame bar I8 of the tractor has an abutment at its rear end which is engageable by the screw |14 in order to limit implement lowering movement of the rock arms 88 and 84. The hydraulic cylinder I2 is connected by a hose I8 with a pump mechanism I8 mounted at the rear of the tractor and operable by the engine I2. The pump mechanism I I8 is attached to a power take-off housing |28 enclosing suitable drive mechanism for the` pump. A control mechanism, not shown, is incorporated in the pump mechanism, which permits, first, delivery of pressure fluid from the pump into the cylinder I|2 at one side of the plunger |I4 to cause movement of the plunger from the starting position in which it is shown in Figs. 1 and 2, to the position shown in Fig. 4, the latter position being reached by a full power stroke of the plunger I I4; second, to stop delivery of pressure fluid to the cylinder |I2 upon completion of the power stroke of the plunger I I4, and at the same time to lock or entrap the pressure fluid in the cylinder II2, which prevents return movement of the plunger from the posivtion in which it is shown in Fig. 4 to the position in which it is shown in Figs. 1 and 2; and third, to release the entrapped fluid in the cylinder H2, which permits return movement of the plunger I|4 from the position in' which it is shown in Fig. 4 to the position in which it is shown in Fig. 1. The valve mechanism is also such as to permit the pump mechanism to idle while the plunger I|4 is in the position of Figs. 1 and 2, and during such idling movement of the pump no pressure fluid is effective in the cylinder II2 at either side of the plunger II4, so that the latter will neither be caused to move outwardly by fluid pressure at one side nor prevented from such outward movement by iluid pressure or by any entrapped duid on the other side. Admission of pressure fluid into the cylinder ||2 causes the plunger ||4 to rotate the cross shaft 32 in an anticlockwise direction with reference to Fig. l, and such anticlockwise rotation of the cross shaft causes the rock arms 33, 94 to move from their implement lowered to their implement raised position. The rearward implement unit is thereby raised from a working to a non-working position, and when the plunger ||4 reaches the end of its power stroke the control mechanism may be operated to stop delivery of pressure fluid to the cylinder ||2 and to entrap the pressure fluid in the cylinder so as to hold the rearward implement unit in its elevated position. Fig. 4 shows the position to which the rock arm 93 will be moved by a full stroke of the plunger ||4, and the corresponding lifted position of the transverse beam |36, the transverse beam |06 being moved into said position by simultaneous upward movement of the rock arms 93 and 94.

The bracket 83 at the left side of the tractor vhas an upwardly extending portion affording a pivot center 81, as has been stated hereinbefore, and swingable on the pivot center 31 is a hand lever comprising a handle bar |2| and a crossbar |22 which is welded to the handle bar |2| and pivoted to the bracket 83 at the pivot center 81. A latch |23 is pivoted on the free end of assures the cross bar |22, and a notched segment |24 engageable by the latch |23 is secured in a fixed position on the bearing boss 36 of the bracket 63. The latch |23 is held by a suitable spring (not shown) in engagement with the notched segment |24 and may be released manually by means of a grip lever |26 which is pivoted on the handle bar |2|, at |21, and connected with the latch |23 by a heavy Wire |28. Pivoted on the rear end of the handle bar |2| at a first pivot center |29 is a ilrst link |3| which has a second pivot center |32 at a distance from the pivot center |29 equal to the spacing of the pivot center |29 from the pivot center 31. Pivotally connected with the first link |3| at the second pivot center |32 is a second link |33 which has a pivotal connection with the arm 93 at a third pivot center |34. Referring to Fig. 3, it will be seen that the second link |33 has a relatively long arm adjacent to the rock arm 93 and a shorter arm adjacent to a second arm |36 of the cross shaft 92, a pin extending through the arms 93 and |36 of the cross shaft and through the arms of the second link |33, affording the mentioned third pivotal connection |34. Another pin extending through both arms of the second link |33 adords the second pivot center |32 on which the first link |3| is connected with the second link |33.

'I'he outer arm of the second link |33 extends beyond the second pivdl'l center |32, and a shoulder pin |31, best shown in Fig. 4, is pivotally connected to the upper end of the second link |33 at a fourth pivot center by means of a pivot pin |38. A tubular rod |39 is telescopically slidable, at its rear end, on the shoulder pin |31, and welded to the forward end of the tubular rod |39 is a nut |4|. An eye-bolt |42 is threaded into the nut |4| and pivotally connected at its eye with the upper end of the lifting arm 13 on the lower draft'link 3| by means of a pivot pin |43. Referring again to the second link |33 at the rear end of the cultivator, a rearwardly and upwardly extending bracket arm |44 is rigidly secured to the second link |33, and a coil spring |46 is hooked at one end into an eye at the upper end of the bracket arm |44. The other end of the spring |43 has a chain connection |41 with a lug |43 on the tubular rod |33.

Pivoted on the pin |33 is another shoulder pin |49 (Fig. 2) corresponding to the shoulder pin |31, and a second tubular rod |3| is telescopically movable at its rear end on the shoulder pin |43. 'I'he second tubular rod |3| is connected at its forward end with the lifting'arm 11 of the lower draft link for the rig beam 14 in the same manner as has been described in connection with the rod |39, that is, an eye-bolt |32 is screwed into a nut at the forward end of the rod |3|, and the eye-bolt |52 is pivotally connected with the lifting arm 11 of the lower draft link for the rig beam 14. .The forward end of the spring |46 has a chain connection |33 with a lug |54 on the rod |3|, as shown in Fig. 2.

The forward implement units at the right side of the tractor comprising the rig beams 13, 13 are operatively connected with the cross shaft 32 by a mechanism which is a duplicate of the mechanism at the left side of the tractor, which has been described hereinbefore, the mechanism at the right side, however, being arranged opposite hand relative to the mechanism at the left side,

.as may be seen from Figs. 2 and 3. The mechanism at the right side of the tractor comprises a handle bar |33 corresponding to the handle bar |2i, the handle bar |36 being swingable about the mentioned pivot center 9| on the bracket 33 at the right side of the tractor and operatively connected with the cross shaft 92 by a first link |31 and second link |38, corresponding to the first link |3| and second link |33. A pair of tubular rods |39, |68 are pivotally and slidably connected with the second link |38 at the right side of the tractor by means of shoulder pins |62, |63 corresponding to the shoulder pins |31 and |49. Eye-bolts |34, |63 adiustably connect the rods |39, |6| with the lifting arms 3|, 32 of the lower draft links for the rig beams 13 and 19. A spring |61' is hooked, at its rear end, into a bracket |68 (Fig. 3) on the second link |33 at the right side of the tractor, and a pair of chains |69, |1| connect the spring |61 with lugs |12, |13 on the rods |33, |3|, respectively.

Considering the operation of the mechanism with reference to the forward implement units at the left side of the tractor, that is, the outer implement unit comprising the rig beam 36, and the inner implement unit comprising the rig beam 14, the following is to be noted. In the operative position of the front and rear implement umts, as shown in Fig. l, the rear end of the tubular rod |39 abuts against the shoulder of the shoulder pin |31, and the rear end of the tubular rod |35 likewise abuts against the shoulder of the shoulder pin |49,'and the screw |14 rests against the abutment on the frame bar |3 of the tractor. The chains |41 and |33 are adjusted to such length that when the mechanism occupies the position shown in Fig. 1 the spring |46 is under considerable tension which will be effective to force the rods |39 and |3| and the shoulder pins |31 and |49 towards each other and cause the rear ends of the rods to bear solidly under considerable pressure against the shoulder pins. at least as long as the front implement umts are not subject to an abnormal upward thrust while they are drawn through the ground. 'Ihe upper and lower draft links 3| and 32, of the outer unit extend rearwardly and downwardly from the bracket 34 at a relatively small angle relas,sso,ssa

endsofthelinks 3|, 32 plus one-halfof the weight of thelinks 3| and .32. 'Ihe shovel 33, when drawn through the ground, develops a. suction force which acts vertically in a downward direction and which, like the mentioned weight of the outerimplement unit and one-'half of the weight of the links 3| and 32, counteracts the lifting l effect of the vertical component of the draft force.

While the tractor advances, the soil resistance encountered by the shovel 33 may vary as the shovel runs into hard and soft spots of the ground and into local rises and hollows of the ground, with the result that the draft force alternately `increases and decreases. A certain soil resists ance, however, may be assumed to. be prevalent kas a normal working condition, and under said normal working condition the combined gravita- `tional and suction forces acting upon the outer implement unit overbalance the vertical component of they draft force. This result is obtained without excessive weight of the implement unit and with ordinary suction of the shovel or shovels Y mounted on the rig beam 53 due to the relatively small angle of the links 3| and 32 relative to the horizontal.

Due to the superiority oi' the combined gravitational and suction forces over the vertical ccmponent of the draft force, under normal working conditions, the lifting arm 13 exerts a rearward push upon the rod |39, which is transmitted to the shoulder pin |31, and augmentsthe pressure of the rod |39 against the shoulder pin |31 set 'upbythespring |43.,'

The inner forward implement unit at the left side of the tractor, that is, the one comprising the rig beam 14, performs in the same manner as has been discussed hereinbefore in connection with the outerl one comprising the rig beam 33. In other words, the rod is likewise subjected to a rearward push under normal working conditions, and such rearward push acts upon the shoulderpin |49 and augments the pressure of the rod III against the shoulder pin |49 set up by the spring |43. Considering for the moment only the combined rearward push of the rods |39 and- .i5l resulting from the gravitational and suction forces of the front implement units at the left side of the tractor, as explained hereinbefore, such combined rearward push acts upon the second link |33 at the fourtlfpivot center |33, and is taken up by the tractor, part of said rearward push being transmitted from said second link to the rock arm 93, cross shaft 32, and addecrease of the draft force. Buch a condition will have no effect upon the position of the shovels because it results merely in an increased rearward push upon the rods |33 and III due to a decrease oi' the vertical components of the drift i'orceswhich counteract the combined'gravitational and suction'forces on the forward implement units at the left side of the tractor. and the increasedrearward push on the rods |33 and. III is taken up at the shoulder pins |33 and |43 which cannot move rearwardly from the position in which they are shown in Fig. l.

'111e result is entirelydierent, however, if the shovels 33 and 13 should run into a hard spot or into a local rise of the ground. In that case the draft forces increase and it may first be assumed y for purposes of explanation that their vertical components become strong enough to balance the combined gravitational and suction forces of the inner and outer forward implement units at the left side ,of the tractor, and alsothe initial tension ofthe spring |43. 'I'his will leave the rods |33 and |9| in the position in which they are shown in Figs. l and 2, but the rods will no longer exert a rearward pressure upon the shoulder pins |31 and |43. Assuming next that the draft forces increase still further, 'it is evident that the rods |33 and Ill will then slide forwardly on the shoulder pins, permitting the front implement units to rise, but upward movement of the front implement umts will be strongly resisted by the spring |43. When the vertical components of the draft forces become strong enough to lift the implement'units against the restraining force of the spring, |43, the resulting upward movement of the shovels 33 and 13 causes a decrease of the soil resistance encountered by the shovels and consequently a decrease of the draft forces. The shovels will therefore rise only an amount sumcient to establish a state of equilibrium between the increased vertical components of the draft forces, at the one handfand the combined gravitational and suction forces plus the tension of the spring |43, on the other hand. In other words, if the shovels run into hard ground or into a local rise of the ground, the shovels will not Ilump out of the ground but stay in and merely ride at a somewhat different depth than under normal working conditions.

Referring to Fig. l, it will be noted thlt the outer front implement unit is connected with the hydraulic Jack ||2, ||4 by a mechanism which comprises two sections, namely, a nrst one .having ilxed pivot centers at 33 and 92, and mvable pivot centers at |43, |33, and |34; and a second section having a fixed pivot center at |23 and a movable pivot center at |32. The rod |33 and the shoulder pin |31 bearing normally solid upon the rock arm 93 may be considered as swingable justing screw |14, and an'other part being transmitted from the second link |33 to the first link |3|, and hand lever |2|, |22, the hand lever |2|, |22 being normally locked on the bracket 33 by means of the latch |23 engagingthe segment |24. As a result, rearward movement of the rods |33 and lil is positively prevented while the screw v|14 engages the abutment gn the frame bar i3 of the tractor and the hand lever |2I, |22 is locked on the :bracket 33.

Assuming now-that the shovels 33 and 13 run into a soft spot or a hollow which will cause a arms of the first section.` The tension of the spring |43 tends to shift the first section towards a position in which the reciprocable link constituted by the link |33 would aline longitudinally with the reciprocable link constituted by the rod |39 and the shoulder pin |31, but such tendency of the spring |43 remains substantially ineffective, in the position of the parts shown in Fig. l, because the line on which the spring |43 acts between the lug |43 and the bracket arm '|44 -of the second link |33 extends in relatively close proximity to the pivot center |33. Operation of assunse I the hydraulic jack comprising the cylinder I |2 and the plunger ||4 so as to swing `the rock arm 33 from the position shown in Fig. 1 to the position shown in Fig. 4, causes the line of action of the spring |46 to move farther away from the pivot center 33, and as the mechanism moves from the position shown in Fig. 1 towards the position shown in Fig. 4, the spring |43 becomes increasingly effective to exert a lifting force upon the front and rear implement units.

The rod 6| and shoulder pin |43 perform in the same manner as the rod |33 and the shoulder pin |31, and what has been said hereinbefore regarding the tendency of the spring |46 to aline the second link |33 with the rod |33 also applies to the rod 'I'hat is, when the mechanism moves from the position shown in Fig. 1 towards the position shown in Fig. 4, the spring |43 becomes increasingly effective to assist upward movement of the rear implement unit and of both forward implement units at the left side of the tractor. The spring |61 at the right side of the tractor functions in the same manner as the spring |46, at the left side of the tractor to assist upward movement of the rear implement unit and of the front implement units at the right side of the tractor.

The springs |46 and |61, therefore, perform two functions, rst to hold the forward implement units in the `ground when the front shovels run into hard ground and under similar adverse operating conditions, and second to facilitate the raising of the front and rear implement units. The latter function of the springs is of particular advantage if instead of a power actuated mechanism such as the hydraulic jack H2', ||4 a manually operated lifting lever is employed.

Referring to the lever comprising the handle bar |2| and cross arm |22, it will be noted that adjustment of this lever about its pivot axis at l1, while the rock arm 33 is positioned as shown in Fig. 1, changes the operating depth of the cultivating shovels 63 and 16. As shown in Fig. 6, adjustment of said lever in a downward direction is effective to swing the reciprocable element constituted by the link |33 rearwardly about the pivot center |34, with the result that the reciprocable elements constituted by the rods |33, |5| and their respective shoulder pins |31 and |43 are moved rearwardly and the shovels 63 and 16 are adjusted to a greater depth of soil penetration than shown in Fig. 1. 0n the other hand, as shown in Fig. '1, adiustment of the lever |2|, |22 in an upward direction from the position in which it is shown in Fig. 1 moves the shovels 63 and 16 to a position of shallower soil penetration. The mechanism at the right side of the tractor, which connects the cross shaft 32 with the implement units comprising the rig beams 13 and 13 operates in the same manner as the mechanism at the left side of the tractor, and what has been said hereinbefore regarding the operation of the hand lever |2|, |22 at the left side of the tractor similarly applies to the hand lever |56 at the right side of the tractor.

Admission of pressure fluid into the cylinder ||2 causes anticlockwise rotation of' the cross shaft 32, as viewed in Fig. 1, and consequently upward movement of the rock arm 33 from the position in which it is shown in said gure. The link |3|, referred to hereinbefore as a first link, being connected with the rock arm 33 through the link |33 which has been referred to hereinment of the rock arm 33, and the second pivot center |32 at which the first link is connected to second link |33 moves in an arc about the first pivot center |23, while the third pivot center |34 at which the second link is connected with the rock arm 33 moves in an arc about the fixed pivot center of said arm at 32. As a result, the fourth pivot center |33 at which the shoulder pin |31 is connected to the second link |33 moves upwardly and forwardly, and the lifting arm 13 is swung forwardly about its pivot center at 63. As stated hereinbefore, the spacing of the second pivot center |32 from the first pivot center |23 is equal, or substantially equal, to the spacing of the first pivot center |23 from the pivot axis 81 of the hand lever 62|, |22 on the bracket 33, and the travel of the plunger ||4 is limited so that at the end of the power stroke of the plunger the second pivot center |32 coincides, or substantially coincides with the pivot axis 31 of the hand lever |2|A |22, as shown in Fig. 4. It will be noted that in the position of the mechanism shown in Fie. 4 the hand lever |2|, |22 may be moved about its pivot center at 31 to any position of adjustment along the segment |24 without causing movement of the link |33 and consequent up and down movement of the front implement units at the left side of the tractor. In other words, irrespective of the position to which the hand lever 82|, |22 has been adjusted to obtain any desired depth of soil penetration of the cultivating shovels 63 and 16 in normal operation, upward movement of the rock arm 33 by a full stroke of the plunger ||4 will raise the cultivating shovels 63 and 16 to a predetermined height above the ground, and the hand lever I2I, |22 may be adjusted to its extreme lower or to its extreme upper position without affecting the height to which the forward implement units are raised above the ground by a full stroke of the plunger ||4.

The mechanism which connects the cross shaft 32 with the front tools at the left side of the tractor therefore functions in the manner of a constant height lift mechanism, and the mechanism which connects the cross shaft 92 with the front tools at the right side of the tractor, being an opposite hand duplicate of the lift mechanism at the left side ofthe tractor, also functions in the manner of a constant height lift mechanism.

In the inoperative position of the cultivator, as shown in Fig. 4, the weight of the implement unit connected with the bracket 54 tends to swing the lifting arm 13 in a rearward direction resulting in a backward push upon the tubular rod |33, and the tubular rods |5|, |53 and |6| are similarly subjected to a rearward push in the raised position of the implement due to the weight of the forward implement units connected with said rods. The rearward push acting upon the rods |33 and |5| in the raised position of the cultivator, due to the weight of the forward implement units at the left side of the tractor, is transmitted in part through the second. link |33 to the rock arm 33, and in part through the second link |33, the first link |3I, handle bar i 2| and cross bar |22 to thepivot center 31 on the bracket 33 which is fixed on the tractor. Similarly, the rearward push acting upon the rods |53 and |6| inthe raised position of the cultivator, due to the weight of the forward implement units at the right side of the tractor, is transmitted in part through the second link |63 to the rock arm 94, and in part through the link |51, handle bar |56 and its cron arm to the bracket 33 on the tractor. The

weight components of the forward implement units rit-the left and right sides of the tractor, which are transmitted to the rockarms 93 and 94 through the links |33 and |53 in the raised position of the cultivator tend to rotate the cross shaft 92 in a clockwise direction as viewed in Fig. 4, andthe weight of the rearwardimplement unit comprising the transverse beam and track eradicating tools |08, |09, also tends to rotate the cross shaft 92 in clockwise direction as viewed in Fig. 4. l

The weight of all forward implement units and the weight of the entire rear implement unit will therefore cooperate to produce a torque upon the cross shaft 92 in a clockwise direction, as viewed in Fig. 4, which torque will become effective to rotate the cross shaft, upon release of the fluid which is entrapped in the cylinder ||2 in order to hold the forward and rearward implement units in their inoperative positions. The clockwise rotation of the cross shaft 92 will continue until the crank screw |14 which is mounted in the bracket |16 on one of the arms I1 of the cross shaft engages the abutment on the right frame bar I8 of the tractor. The depth to which the track eradicating tools penetrate the ground may be adjusted by rotation of the crank screw |14, while the normal depth to which the forward cultivating shovels penetrate the ground may be adjusted by the hand levers |2| and |59 as has been explained hereinbefore.

When the lift mechanisms at the right and left sides of the tractor are operated by a power stroke of the hydraulic jack ||2, ||4 the springs |46 and |81 contract to 'some extent, and clockwise rotation of the cross shaft 92 from the position shown in Fig. 4 into the position shown in Fig. l will elongate the springs, with the result that a substantial part of the potential energy of the raised front and rear implement units will assasss push in spite of the slackening of the chain |33. However, the rearward push of the rod ill is relatively small compared with the forward pull on the rod |39, which has been assumed to be sumcient to overcome the initial tension of the spring |49, and when the mentioned conditions are incurred the link |33 therefore becomes subject to a forward pull which tends to swing it forwardly about the pivot center |34 on the rock arm 93. A similar tendency of the link |33 to swing forwardly about the pivot center |34 while the rock arm 93 is in its implement lowered position occurs whenever the draft forces upon the front implement units at the left side of the tractor increase to such an extent that the gravitational and suction forces are no longer sumcient to hold said implement units in their working positions.

In the position of the mechanism as shown in Fig. 6 the link |33 is practically prevented from swinging forwardly about the pivot center |34 whenever one or both of the forward implement units at the left side of the tractor should become subjected to an abnormally strong upwardly directed reactive force, and which condition may be incurred, as stated, when a rock, or l.l

units atthe left side of the tractor. In the pobe stored in the springs by gravitational movement of the front and rear implement units from their raised to their lowered positions. The energy thus stored in the springs becomes effective upon upward movement of the rock arms 93 and 94, to cause a reduction of the lifting effort for moving the front and rear implement units to their inoperative positions, as has been mentioned liereinbefore. Clockwise rotation of the cross shaft 92 towards the position in which it is shown in Fig. `1 will also be effective to return the plunger ||4 to its starting position within the `cylinder H2, and the return movement of the plunger will transfer the fluid from the cylinder I2 through the hose I9 back into a sump within the power take-o housing |20.

When the machine traverses a field with the tools lowered to operative positions, a stone or other obstruction may be encountered by one of the front shovels, and the corresponding rig beam may be forced upwardly from its normal operating position. Assuming that such action takes place on the rig beam 56, it wil1 be seen that the rod |39 will be pulled forwardly, but such forward pull willr not be transmitted to the adjacent rc-d |5I, since the chain |41 takes the whole pull, while the chain |53 slackens and relleves the rod |5| from the tension of the spring |46, but the rig beam 14 will not rise as long as the soil resistance encountered by the shovel or shovels of the -rig beam 14 remains normal, in which case the gravitational and suction forces on the rig beam 14 overbalance the vertical component of the draft force transmitted to the rig beam 14, and the rod IBI is subject to rearward sition of the mechanism as shown in Fig. 6, the first link |3| occupies a toggle position relative to the reciprocable link or thrust element constituted by the rod |39 and shoulder pin |31; and the first link is subject to compression by' a forward pull on one or both of the-rods |39 and Ill, which is transmitted 4to the spring |49 and to the second linkv |33. Due `to the mentioned toggle position, the rst link |3| is eectively prevented, or at least substantially restrained from swinging upwardly about its first pivot eenter |29; the second link |33 is effectively prevented or at least substantially `restrained from swinging forwardly about the third pivot center |34; and the position of the rock arm 93 is such that the rock arm 93 is also effectively prevented Vor at least substantially restrained from swingi strong upwardly directed reactive force, the part of the mechanism comprising the rock arm 33.

the.rst link |3| and the second link |33 will be effectively prevented or at least substantially restrained from moving out of the position in which it is shown in Fig. 6, although the hydraulic jack ||2, ||4 is practically ineffective to restrain upward movement of the rock arm 33. The accomplishment of this result is also largely independent of any other restraining force upon the rock arm 93, such as the gravitational force of the rear implement unit.

` Referring to Figs. l, 6 and '1, it will be noted that the mentioned toggle position of the first link |3| is aifected very little by up and down adjustment of the hand lever |2I,` |22;` and up ward and forward swinging movement of the second link |33, and upward swinging movement of the rock arm 93 will be effectively opposed in the manner mentioned hereinbefore, in any po. sition of adjustment of the hand lever 2|, |22.

As stated hereinbefore, the chains |41 and |33 are adjusted to such lengths that when the mechanism occupies the position shown in Fig. l, the spring |49 is .under considerable tension, and `adjustment of the hand lever |2I, |22 from the position shown in Fig. l to the position shown in Fig. 6, while the rock arm 93 is in its implement lowered position, will be effective to increase the tension of the spring |49 to some extent. The lifting effect of the spring |46 upon the front and rear implement units, however, is relatively low in any position to which the hand lever |2I, |22 may be adjusted while the rock arm 93 is in its implement lowered position, and the spring |49, therefore, may be tensioned considerably without subjecting the front and rear implement umts to an appreciabledlifting effect by the spring |49 while the link I3I occupies the mentioned toggle position. It will be noted that the toggle position of the first link |3I relative to the reciprocable link |39, |31, or the toggle position of the reciprocable link I 39, |31 relative to the first link |3| is such as to afford a relatively small lever ratio between the lifting arm 13 and the first link |3I, and so as to afford a relatively large lever ratio between the rock arm 93 and the first link |3I.

When the mechanism occupies the position shown in Fig. 6, and the rod |39 becomes subjected to a forward pull, as mentioned hereinbefore, such forward pull may be considered, for purposes of analysis, as being equivalent to a forward pull on the dash-dotted line A through the fourth pivot center |38 and through the point at which the rod |39 is pivoted on the lifting arm 13 by means of the pivot pin |43, the line A representing the effective line of thrust on which the thrust element comprising the rod |39 is positioned when the front implement unit is in its working position and the rock arm 93 'is in its implement lowered position. 'I'he dash-dotted line B through the first pivot center |29 and through the second pivot center |32 intersects the dash-dotted line C through the third pivot center |34 and through the pivot center or pivot axis 92 at a point X, and the line A extends in close proximity to said point X. If the line A would extend 'exactly through the point X the link and lever system connecting the front implement unit at the left side of the tractor with the hydraulic jack ||2, I|4 would be in a dead center position, from which' it could not be moved by any force acting forwardly on the line A. It should be noted, however, that the link and lever system could be moved very readily out of said dead center position by the admission of fluid pressure into the hydraulic cylinder I I2, or by the application of a rotative force to the rock arm 93 in any other manner, which would tend to swing the rock arm 93 upwardly from its implement lowered to its implement raised position. The link andflever -system has pivot centers on the traveling support, at 92 and at |29, and a pivot center on the lifting arm 13 at |43, and the link and lever system is so arranged that when the lifting arm 13 occupies its implement lowered position and the plunger H4 or actuating element occupies its starting position, the link and lever system occupies a toggle position sufficiently close to said dead center position to afford a relatively high initial resistance against movement thereof out of said toggle position in ay direction away from said dead center position under a reactive force upon the outer front implement unit at the left side of the tractor, or upon the lifting arm 13, and a relatively low resistance against shown in Fig. 6 to the position shown in Fig. '1,

the intersection point X moves on the line C a very short distance towards the pivot axis 92. and adjustment of the hand lever or adjustable element is therefore substantially ineffective to displace the intersection point X relative to the machine. 'I'he line A moves somewhat away from the intersection point X when the hand lever is adjusted from the position'shown in Fig. 6 to the position shown in Fig. 7, but it still extends in relatively close proximity to the intersection point X. In other words, any position to which the link and lever system may be adjusted by movement f of the hand lever I 2|, |22 when the lifting arm 13 and the rock arm 93 are in their implement lowered positions, will be sufliciently close to the mentioned dead center position to afford a relatively high initial resistance against movement of the link and lever system under a reactive force upon the lifting arm 13 and a relatively low reslilsganclz: against operation by the hydraulic jack The foregoing considerations similarly apply to the implement unit comprising the rig beam 14 which is operatively connected with the rod ISI. The implement adjusting mechanism at the right side of the tractor and the front implement units comprising-the rig beams 18 and 19 perform in the same manner as the implement adjusting mechanism at the left side of' the tractor and the front implement units comprising the rig beams 56 and 14; and what has been said hereinbefore about the link and lever system at the left side of the tractor also applies to the implement adjusting mechanism at the right side of the tractor.

While in the foregoing a preferred embodiment of the invention has been described with reference to the drawings, it should be understood that it is not intended to limit the invention to the exact details of construction herein shown and described, for variou-s modifications within the scope of the appended claims may occur to persons skilled ln the art.

It is claimed and desired to secure by Letters Patent:

l. In an agricultural machine, a traveling support, an implement movably mounted on said traveling support, and adjusting means for said implement comprising, a lever pivotally adjustable on said traveling support to different positions, a first link having relatively spaced pivot centers, one fixed on said lever at a distance from the pivot axis thereof substantially equal to the spacing between said pivot centers to permit movement of said first link into a registering position in which the other pivot center of said first link substantially coincides with the pivot axis of said lever, a second link pivotally connected with said first link at said other pivot center thereof, a rock arm pivotally connected with said second link and swingable on said traveling support about a xed center spaced from the pivot axis of said lever, actuating means operatively connected with said rock arm for moving said first link into and out of said registering position thereof, and means operatively connecting said implement with said links.

2. In an agricultural machine, a traveling suptraveling support, and adjusting means ior said lement comprising, a lever pivotalb. adjust- 'ie on said traveling support-to diilerent positions. a rst link having relatively "spaced pivot.

centers, one fixed on said lever at a distance from the pivot axis thereof substantially equal to the spacing between said pivot centers to permit movement of said iirsvlink into a registering position in which the other pivot center or said rst link substantially coincides with the pivot axis of` said lever, a second link pivotaliy connected with said nrst link at said other pivot center thereof, a rock arm pivotaliy connected with said second link an swingable on said traveling support about a center spaced from the pivot axis of said lever, actuating means operatively connected with said rock arm for moving said ilrst link into and out of said registering `position thereof, and an operating connection between said rock arm and said implement comprising a reciprocable element pivoted on said second link'and operatively connected with said im ment.

In an agricultural machine, a traveling supprt, a lever pivotaliy adjustable. on said traveling support to diii'erent positions, a iirst link l having relatively spaced pivot centers, one fixed on said lever at a distance from the pivot axis thereof substantially equal to the spacing between said pivot centers of said first link to permit movement of the latter into a registering position in which the other pivot center of said iirst link substantially coincides with the pivot axis of said lever, a second .link pivotaliy connected with said ilrst link at saidother pivot center thereof, a rock arm having a fixed pivot center on said traveling support and pivotaliy connected with said second link, actuating means cooperating with said rock arm for moving said iirst link into and out'of said registering position. a ilrst implement unit movably mounted on said traveling support, an operating connection between said rock arm and said first implement unit comprising a reciprocable element pivoted on said second link and operatively connected with said first implement unit, and a second implement unit connected with said rock arm for movement thereby relative to said traveling support. I

4. In an agricultural machine, a traveling support, a lifting arm and a rock arm pivotally mounted independentlyof each other on said traveling support, a link swingable about a pivot center on said traveling support, means connecting one of said arms with said link, and a reciprocable element operatively connected with the other of said arms and with said connecting means, whereby said reciprocable element and link may be moved into a {predetermined toggle position relative toieach other, ail'ording a relatively-small lever ratio between said lifting l arm and said link, and a relatively large lever ratio between said rock arm and said link, and first and second implement unitsconnected, re-

' spectively, with said arms independently of said connecting means and tending, by their weight, to move said reciprocable element and link towards said toggle position.

5. In an agricultural machine, a traveling support, a lifting arm and a rock arm pivotaliy molmted independently of each other on said travelingsupport, a link swingable about a pivot center on said traveling support, means connecting one of said arms with said link, and a a,aso,ses ,A

reciprocable element operatively connected withthe other said arms and with saidJ connecting means, whereby said reciprocable element and link may be moved into a predetermined toggle position relatlveto each other., aiiording a relatively small lever ratio between said lifting arm and said 1min-'and a relatively large lever 4ratio between said rock arm and said link, iirst and second implement units connected, respectively. with said arms independently of said connecting means and tending, by their weight,

to move said reciprocable element and link towards saidy toggle position, eratively connected with said rock armtfor preventing said reciprocable element from' moving beyond said toggle position.

6. In an agricultural machine, a traveling support, a lifting arm and a rock arm pivotaliy mounted independently of each other on said traveling support, a I ink swingable about a pivot -center on said traveling support, means connecting one ofsaid arms with said link. and a reciprocable element operatively connected with the other of said arms-and with said connecting means, whereby said and stop means opposition relative to each other, affording a relatively small lever ratio between said lifting arm and said link, and a relatively large` lever ratio between said rock arm and said link, iirst and second implement units connectedrespectively, with said arms independentlymf said` connecting means and tending, by their weight, to move said reciprocable element and link towards said toggle position, and adjustable relatively abuttable elements, one operatively connected with said `rock arm and the other with said traveling support fpr preventing said reciprocable element from moving beyond said toggle position.

'7. In an agricultural machine. a traveling support, a lifting arm and a rock arm pivotaliy mounted independently of eachother on said traveling support, a lever adjustable to diiIerent positions about a ilxed pivot center on said traveling-support, a link swingable about another pivot center on said lever spaced from said fixed pivot center, means independent of said link for locking said lever in diii'erent positions of adjustment, means connecting one of said arms with said link, a reciprocable element operatively connected with the other of said arms and with said connecting means whereby said reciprocable element and link maybe moved into a toggle position relative to each other, in any pivotaliy adjusted position of said lever, anordlng a relatively small lever ratio between said lifting arm and said link, and a relatively large lever ratio between said rock arm and said link. rst and second implement units connected, respectively, with said arms independently of said connecting means and tending, by their weight,

to move said reciprocable element and link to' and stop means opreciprocable element .and link may be moved into a predetermined toggle i stop means including connecting said reciprocable element with said thrust transmitting connection, whereby movement of said arms in one direction will move said reciprocable element into a predetermined toggle position relative to said link, affording a relatively small lever ratio between said lifting arm and said link, and a relatively large lever ratio between said roclnarm and said link, and whereby movement of said rock arm in the opposite direction will positively move said reciprocable element from said toggle position, first and second implement units connected, respectively, with said arms independently of said thrust transmitting connection and tending, by their weight, to move said arms in said one direction, and a one-way actuating mechanism operatively connected with said rock arm and operable to move said reciprocable element from said toggle position for raising said implement units.

9. In an agricultural machine, a traveling support, a lifting arm and a rock arm pivotally mounted independently of each other on said traJveling support, a first link swingable about a pir ot center on said traveling support, a second link pivotally connected with said rst link and with said rock arm, a reciprocable element operatively connected with said links and with said lifting arm, whereby said reciprocable element may be moved into a toggle position relative to said first link affording a relatively small lever ratio between said lifting arm and said first link, and a relatively large lever ratio between said rock arm and said first link, and first and second implement units connected, respectively, with said arms independently of said second link and tending, by their weight, to move said reciprocable element towards said toggle position.

10. In an agricultural machine, a traveling support, a first implement unit mounted on said support for up and down movement relative thereto, a lifting arm connected with said first implement unit and swingable, by gravitational movement of said firstl implement unit. into an implement lowered position. a rock arm having a fixed pivot center on said traveling support. a pair of pivotally connected links having pivot centers, respectively, on said traveling support and on said rock arm, a second implement unit connected with said rock arm, independently of said links, and tendingr by its weight to move said rock arm towards an implement lowered position, actuating means connected with said rock arm and operable to move said rock arm to an` implement raised position, and a reciprocable element connected with said lifting arm and with one of said links, said reciprocable element, links and rock arm being so arranged that when said lifting and rock arms occupy saidimplement lowered positions, respectively, said rock arm. links and reciprocable element occupy a toggle position sufficiently close to a dead center position thereof to afford a relatively high initial resistance against movement out of said toggle position under a reactive force upon said first implement unit, and a relatively low resistance against said movement thereof out of said toggle position by movement of said rock arm towards an implement raised position by operation of said actuating means.

11. In an agricultural machine, a traveling support, an implement unit mounted on said support for up and down movement relative thereto, a lifting arm connected with said implement unit and swingable, by gravitational movement of said implement unit, into an imein plement lowered position, a hydraulic jack mounted on said support comprising a cylinder and a piston movable therein from a starting position by admission of fluid pressure into said cylinder at one side of said piston, a rock arm having a fixed pivot center on said traveling support, means connecting said rock arm with said piston, a pair of pivotally connected links having pivot centers, respectively, on said traveling support and on said rock arm, and a reciprocable element connected with one of said links and with said lifting arm for moving said lifting arm from its implement lowered to an implement raised position by said admission of fluid pressure into said cylinder and for returning said piston to said starting position, upon release of said uid pressure, by said gravitational movement of said implement unit, said rock arm, links and reciprocable element and being so arranged that when said lifting arm and said piston occupy said implement lowered and said starting positions, respectively, said rock arm, links and reciprocable element occupy a toggle position sufciently close to a dead center position to afford a relatively high initial resistance, independently of said hydraulic jack, against movement thereof out of said toggle position under a reactive force upon said implement unit and a relatively low resistance against said movement thereof out of said toggle position by said admission of pressure fluid into said cylinder.

12. In an agricultural machine, a traveling support, a, lifting arm and a rock arm swingable on said support from implement lowered to implement raised positions, and vice versa, a pair of pivotally connected first and second links having pivot centers. respectively, on said traveling support and on said rock arm, a reciprocable element pivoted at one end thereof on said lifting arm and having a pivotal supporting connection, at its other end, on said second link, and first and second implement units operatively connected, respectively with said lifting and rock arms, independently of said second link, said rockarm,links and reciprocable element being so arranged that when said arms occupy said implement lowered positions, said rock arm, links and reciprocable element occupy a toggle position sufficiently close to a. dead center position to afford a relatively high initial resistance against movement thereof out of said toggle position under a reactive force upon said lifting arm and a yrelatively low resistance against said movement thereof out of said toggle position by said movement of said rock arm from .its implement lowered to its implement raised position.

13. In an agricultural machine. a traveling support, .a rock arm swingable on said support from implement lowered to implement raised positions. and vice versa, a hydraulic jack mounted on said support comprising a cylinder and a piston movable therein from a starting position by admission of pressure fluid into said cylinder at one side of said piston, means connecting said hydraulic ,ia-ck with said rock arm for swinging the latter from its implement lowered to its implement raised position by said admission of pressure fluid into said cylinder and for returning said piston to said starting position by movement of said rock arm from its implement raised to its implement lowered position, a pair of pivotally connected first. and second links having pivot centers, respectively, on said traveling support and on said rock arm, a rst -implement unit mounted on said support f movement relative thereto from a lowered to a for raised position, and vice-versa, a thrust transmitting element connected to said first `implement unit and to said second link, so that when said rock arm is in its implement lowered position said thrust transmitting element, links and rock arm occupy a toggle position sufficiently close to a dead'center position to afford a relatively high initial resistance, independently of said hydraulic jack, against;l movement thereof out of said toggle positionunder a reactive force upon said first' implement unit, and a relatively low resistance against said movement thereof out of said toggle position by said movement of said rock arm from its implement lowered to its irnplement raised position and second implementunit connected with said rock arm independently of said second link, whereby admission of pressure fluid into said cylinder will Ibecome eifectiveto raise said first and second implement units, and gravitational movement of said first and second implement umts from their raised positions, upon release of fluid pressure within said cylinder will become effective to return said piston to its starting position.

14. In an agricultural machine. a traveling support, a lifting arm and a rock arm swingable on said support from implementlowered to implement raised positions, and vice versa, actuating means connected with said rock arm for swinging said rock arm from an implement lowered to an implement raised position, a control element adjustably mounted on said support and lockable in different positions of adjustment rela- 'tive thereto, a pair of pivotally connected nrst and second links having pivot centers, respectively, on said control element and on said rock arm, a reciprocable element connected with said lifting arm and with said second link, operable to transmit swinging movement of said rock arm by said actuating means, to said lifting arm and to adjust the implement lowered position of said lifting arm relative to the implement lowered position of said rock arm by adjustment of said control lelement, said reciprocable element and links being so arranged that any of the positions thereof to which they Ymay be moved by adjustment of said control element while said rock arm is in its lowered position, will be sufficiently close to a. dead center position to place said reciprocable element, links vand rock arm into a toggle position affording a relatively high initial resistance against movement of said reciprocable element, links and rock arm out of said toggle position under a reactive force upon said lifting arm, and a relatively low resistance against said movement thereof out of said vtoggle position when said actuating means are op'erated to swing said rock arm from its implement lowered to its implement raised position.

15. In an agricultural machine, a traveling support, an implement unit mounted on said support for up and down movement relative thereto, a lifting arm connected with said implement unit and movable about a fixed pivot center on said support from an implement lowered to an implement raised position, and vice versa, a first link having a. first pivot center on said support and a second pivot center swingable about said first pivot center, a rock arm having a fixed pivot center on said support, a second link having a pivot connection with said first link at said second pivot center and another pivot connection,

at a ,third pivot center, with said rock arm in 1| assasss such relation to said fixed pivot center of the latter that movement of said rock arm about its fixed pivot center in one direction will cause movement of said first link about said first pivot center in the same direction, a reciprocable elenient having a pivot connection at a fourth pivot center with said second link, means pivotally connecting said reciprocable element with said lifting arm, at a point movable about said fixed pivot center thereof by said movements of said lifting arm, and. means for moving said rock arm about its fixed pivot center from. a first to a second predetermined position, whereby said lifting arm will be moved from its implement lowered to its implement raised-position, the relative arrangement of said pivot-centers being such that when saidflifting and rock arms are in said implement lowered and first predetermined positions, re-

spectively. a line extending through said first and4 second pivot centers, and 'a1-line extending through the fixed pivot center of said rock arm and through said third pivot center intersect each other at a point in proximity to a line extending through said point on said lifting arm and through said fourth pivot center.

16. In an agricultural machine, a traveling support, a first implement unit mounted on said support for up and down movement relative thereto, a lifting arm connected with said first implement .unit and movable by gravitational movement of said first implement unit, about a fixed pivot center on said support from an implement raised to an implement lowered position. a first link having a first pivot center on said support and a second pivot center swingable about said first pivot center, a rock arm having a fixed pivot center on said support and a third pivot center movable therewith about said fixed pivot center of said rock arm, a second link having pivot connections with said rst link and with said rock arm at said second and third pivot centers. respectively, a second implement unit connected with said rock arm independently of said second link, whereby gravitational movement of said second implement unit will become effective to swing said rock arm about said fixed pivot center thereof, a reciprocable element having a pivot connection at a fourth pivot center with said second link, means pivotally connecting said reciprocable element with said lifting arm at a point movable about said fixed pivot center thereof by said movement of said lifting arm, a hydraulic jack mounted on said support comprising a cylinder and a piston movable therein from a starting position by admission of fluid pressure into said cylinder at one side of said piston, and means operatively connecting said rock arm with said hydraulic jack whereby said first and second implement units will be moved from lowered to raised positions by said admission of iiuid pressure into said cylinder and whereby said piston will be returned to said starting position, upon release of said iiui pressure, by said gravitational movement of said implement units, the relative arrangement of said pivot centers being such that when said lifting arm and said piston are in said implement lowered and start.

ing positions, respectively, a line extending .through said first and second pivot centers, and a line extending through the fixed pivot center of said rock arm and through said third pivot center intersect each other at a point in proximity to a line extending through said point on said lifting arm and through said fourth pivot center. l

17. In an agricultural machine, a traveling support, an implement unit mounted on said support for up and down movement relative thereto, a rock arm movable about a fixed pivot center on said support from a first to a second predetermined position, and vice versa, a first link having a rst pivot center on said support and a second pivot center swingable about said first pivot center, a second link swingably connected at said second pivot center with said first link and at a third pivot center with said rock arm in such relation to said fixed pivot center of the latter that movement of said rock arm in one direction about its fixed pivot center will cause movement of said first link in the same direction about said first pivot center, a thrust element pivoted on said second link, and means operatively connecting said thrust element with said implement unit, whereby movement of said rock arm from said rst to said second predetermined position will raise said implement unit from a working to a non-working position, said connecting means being so arranged that when said implement unit and said rock arm are in their working and iirst predetermined positions, respectively, said thrust element Will be positioned on an effective line of thrust in proximity to the point at which a line through said first and second pivot centers intersects a line extending through said third pivot center and through said fixed pivot center of said rock arm.

18. An implement adjusting mechanism for agricultural machines, comprising a rock arm movable about a xed pivot axis on the machine from a first to a second predetermined position, and vice versa, an adjustable element lockable in different positions of adjustment on the machine, a first link having a first pivot center on said adjustable element, a second link having a second and a third pivot center on said first link and on said rock arm, respectively, at predetermined spacings from said first pivot center and from said pivot axis, so proportioned and arranged that when said rock arm occupies said first predetermined position a line through said first and second pivot centers and a line through said third pivot center and through said pivot axis intersect each other and so that movement of said adjustable element will be substantially ineffective to displace the intersection point of said lines relative to the machine. means operatively connected with said second link including a thrust element operable by movement of said adjustable element and by movement of said rock arm from its first to its second predetermined position to transmit adjusting movement to an implement, and means cooperating with said thrust element to position the latter, when said rock arm is in its first predetermined position, on an effective line of thrust in proximity to said intersection point.

19. In an agricultural machine, a traveling support, an implement unit mounted on said support for up and down movement relative thereto,

a lifting arm connected with said implement unit and movable in a generally fore and ait direction for raising and lowering said implement unit, a rock arm movable about a ixed pivot axis on said support in a generally up and down direction between first and second predetermined positions, an adjustable element movable in a generally fore and aft direction on said support and lockable in different positions of adjustment, a first link having a first pivot center on said adjustable element in vertically spaced relation to said pivot axis, a second link having a second and a third pivot center on said first link and on said rock arm, respectively, at predetermined spacings from said first pivot center and from said pivot axis, so proportioned that said first link may be moved in a fore and aft direction and said second link may be swung in a fore and aft direction about said third pivot center by adjustment of said movable element while said rock arm occupies said rst predetermined position, and connecting means between one of said links and said lifting arm for transmitting movement of said adjustable element to said lifting arm and for moving said lifting arm to raise said implement unit by movement of said rock arm from said first to said second predetermined position.

20. An implement adjusting mechanism for agricultural machines. comprising a rock arm movable about a fixed pivot axis on the machine from a first to a second predetermined position, and vice versa. a lever pivotally adjustable on the machine to different positions, a iirst link having a first pivot center on said lever at a predetermined spacing from the pivot axis of said lever, a second link having a second pivot center on said first link at a predetermined spacing from said first pivot center substantially equal to said predetermined spacing of said first pivot center from the pivot axis of said lever, said second link having a third pivot center on said rock arm and being arranged so that, when said rock arm occupies said first predetermined position, a line through said first and second pivot centers and a line through said third pivot center and through the pivot axis of said rock arm intersect each other, irrespective of adjustment of said hand lever, at a point in substantially fixed relation to the machine, and so that when said rock arm occupies said second predetermined position said second pivot center substantially coincides with the pivot axis of said lever, means operatively connected with said second link including a thrust element operable by movement of said lever and by movement of said rock arm from its first to its second predetermined position to transmit adjusting movement to an implement, and means cooperating with said thrust element to position the latter, when said rock arm is in its first predetermined position, on an effective line of thrust in proximity to said intersection point.

WALTER G. CHARLEY.

CERTIFICATE CF CORRECTION'.

Patent No.- 2,55o,58. June 6, 191m.

WALTER C. CHARLEY.

It is hereby Certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 12, first ilcolumn, line 50, claim 1li, before "lowered" insert "implement-f; and that 'the said Lei-,ters Patent should be read with this correction therein met the same may confon'n to the record of the' case vin the 'Patent Office.

Signed and sealed this 8th day of August, A.v D. 19141;..

(S651) Acting Commissioner of Patents.

cERTFIcATE oF CORRECTION'.

Patent No.- 2,550,58. June 6, 191m.

WALTER G. CHARLEY.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 12,' first column, line 50, 'claim lll., before "lowered" insert 1mp1ement and that Vthe said Letters Patent should be read with this correction therein that the same may confon to the record of the' case vin the Patent Office.

Signed and sealed this 8th day of August, A.. D. 191414.. v

Leslie Frazer-.

(39,1) Acting Commissioner of Padzents.A 

